Method of and apparatus for preparing facsimile master copies



Nov. 3, 1942. DHUMY HAL 2,301,024

METHOD OF AND APPARATUS FOR PREPARING FACSIMILE MASTER COPIES I FiledNOV. 1, 1940 '7 Sheets-Sheet l A A, i:

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METHOD OF AND APPARATUS FOR PREPARING FACSIMILE MASTER COPIES Filed Nov.1, 1940 7 Sheets-Sheet 2 INVENTORS -4o5$ F.. D'HUMY j of wzm 2531.551 c;L 434 BY swag: s

F. E. DHUMY ETAL Nov. 3, 1942.

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METHOD OF AND APPARATUS FOR PREPARING FACSIMILE MASTER COPIES NVENTORS 1IDIP BY F L:

ATTORNEY Nov. 3,1942. F. E. DHUMY HAL. I 2,301,024

METHOD OF AND APPARATUS FOR PREPARING FACSIMIIVJE MASTER COPIES PatentedNov. 3, 1942 UNITED STATES PATENT OFFICE METHOD OF AND APPARATUS FORPREPAR- A ING FACSIMILE MASTER COPIES Application November 1, 1940,Serial No. 383,928

(Ci. PIS-8.8)

23 Claims.

This invention relates to improved methods of and apparatus forreproducing facsimile copies, in any desired number, of pictures,drawings. writing and other subject matter, and more particularly topreparing a master copy of an original, from which numerous copies maybe made by the Mimeograph, hectograph and other printing processes.

In accordance with the present invention, a picture, message or othersubject matter is transmitted from a subject matter sheet or blank andreproduced upon a recording blank which may, if desired, comprise amaster blank from which a large number of copies may be made by variousknown printing and other duplicating processes. The transmitting andrecording blanks are carried by interchangeable copy holders, such asrotatable cylinders or drums that are scanned by the combinedtransmitting and recording apparatus during the reproducing operation,which can readily be placed into operative position in the transmittingand recording apparatus and can readily be removed therefrom.

The blanks on which the original subject matter appears often vary insize, and the subject matter to be scanned may vary considerably inarea, and heretofore it has been necessary to utilize transmitting drumsof sufllciently large diameter to accommodate the largest size of blankor the largest area of subject matter to be scanned. Th s has resultedin a considerable loss of time when smaller blanks or smaller areas ofsubject matter are scanned, since it has required approximately the sametime to transmit and record the same as that required for the largerblanks or larger areas of subject matter. Accordingly, one object of theinvention is a combined transmitter and recorder in which drums ofdifferent diameters may readily be employed to accommodate subjectmatter blanks of different sizes.

Another object is apparatus of the character d sclosed in which thescanning elements of the transmitting and recording apparatus arereadily and accurately adjustable with respect to the transmitting andrecording drums of copy holders so that copy holders of different sizesmay be employed, while maintaining the proper spacing between thetransmitter scanning element and the original sheet, and between therecording scanning elements and the facsimile copy, to insure propertransmission and proper .reproduction irrespective of the size of thedrum or copy holders employed.

A further object of the invention is transmitter-recorder apparatus inwhich the facsimile copy of an original may be made on the same scale asthe original or may be enlarged or reduced with respect to the originalwithout distortion of the subject matter thus reproduced, and in which afacsimile master copy may be made either on a fibrous sheet or on ametal sheet or other suitable reproducing medium.

Still another object is facsimile transmitterrecorder apparatus havingmeans for causing the linear scanning speed of the-transmitting andrecording drums to be maintained at a constant predetermined value,notwithstanding that drums of different diameters are employed, andmeans for insuring the proper line feed of the scanning elements for thedifferent sizes of drums.

An additional object is to provide improved circuit arrangements forinterconnecting the transmitter and recorder of a unit of the characterdisclosed.

Still further objects are to provide a more compact and eflicienttransmitter-recorder unit; to facilitate the insertion, removal andhandling of the transmitting and recording drums, and the application ofthe subject matter blanks thereto and removal therefrom; to provideimproved definition of the reproduced subject matter; to enable the useof separate transmitting and recording drums concurrently, which drumsmay be of the same size or of different sizes, respectively; to enablethe subject matter on the original to be reproduced on the recordingblank in a manner to provide either a positive or negative copy thereof;and to provide suitable safety means to prevent injury to the subjectmatter blanks due to accidental contact with the scanning stylus of therecorder.

The foregoing and other objects and advantages of the invention willappear from the following description of the illustrative embodiments ofthe invention.

Referring to the drawings:

Fig. 1 is a plan view of one embodiment of a transmitter and recorderunit embodying the invention:

Fig. 2 is a front view in elevation of the apparatus of Fig. 1, withcertain portions broken away in order more clearly to show otherportions thereof;

Fig. 3 is a section taken along the line 3-3 of Fig. 1, showing certaindetails of the driving gear mechanism employed;

Fig. 4 is a section taken along the line 4-4 of Fig. 2, showing certaindetails of the recording unit;

Fig. 5 is a view similar to Fig. 4 with certain portions broken away;

Fig. 6 is a detail view of a switch control device employed in therecording unit;

Fig. 7 is a plan view of another embodiment of the invention;

Fig. 8 is a fragmentary view of the recording drum and recording blankshown in Fig. 7;

Fig. 9 is a section taken along the line 9-9 of Fig. 8;

Figs. 10 and 11 are plan and side views, respectively of a device forpreforming the recording blank shown in Figs. '7 and 8;

Fig. 12 is a section taken along the line i'-il2 of Fig. 10;

Fig. 13 is a fragmentary sectional view taken along the line iii-43 inFig.

Figs. 14 and 15 show the method of preforming the recording blank ofFigs. Ti and 6;

Fig. 16 is a plan view of a modified form of drum holding mechanism;

Fig. 17 is a section taken along the line ill of Fig. 16;

Fig. 18 shows a modification of the arrange ment of Fig. 15;

Fig. 19 illustrates diagrammatically the electrical features of acircuit which may be employed to interconnect the transmitter andrecorder; and

Fig. 20 illustrates diagrammatically certain control features of thetransmitter and recorder apparatus.

Referring to the drawings, and particularly to Figs. 1 and 2 thereof, abase 20 forms the principal support for the apparatus and driving andcontrol mechanism therefon which base is adapted to rest upon anapparatus table or cabinet or other convenient support, a cabinetpreferably being employed so that certain of the power unit andamplifier devices employed may be embodied therein.

Secured to plates 20a and 20?) on the base 20 are brackets 2| in whichare mounted a front track or guide rail 22 and a rear track or guiderail 23 which slidably support the longitudinally movable transmittingscanning assembly 25 and the recording scanning unit 26. Preferably, andas shown, the transmitting scanning unit 25 comprises an optical pickupsystem for deriving signals from an original blank 29 which carries thesubject matter to be reproduced or duplicated, the blank being securedupon a cylindrical drum portion 30 of a copy holder which is indicatedin its entirety by the reference numeral 3 I. The copy holder 3|includes a cylindrical drum portion 34 adapted to support a recordingblank or master copy 35 which is acted upon by the stylus 33 of therecording unit 26.

The transmitter scanning assembly 25 and the recording unit 26 arerespectively mounted on base or carriage members 36 and 31, which basemembers are provided with a suitable number of front guide blocks 38 and39 slidably mounted on the front guide rail 22, the carriage membershaving rollers 40 and 4| which cooperate with the guide rail 23 tofacilitate travel of the units 25 and 28 along the guide rails. Thecarriage member 31 of the recording unit is secured to the carriagemember 36 of the transmitting unit, as by a carriage link 42, shown inFig. 2, so that any movement of the recording unit longitudinally alongthe guide rods 22 and 23 will impart a similar movement to thetransmitting unit 28 and vice versa.

Power for operating the apparatus is supplied by the motor 50, whichpreferably is of the synchronous alternating current type, or, ifdesired. may be of the direct current type, it being understood that, ifnecessary, the speed of the motor for any given operation my be adjustedand maintained constant by any of the various suitable means known inthe art for this purpose. The power preferably is applied by the motor50 through the medium of a reducing gear mechanism 5i. Secured to androtatable with the driving shaft $2 of the reducing gear mechanism aredriving gears and 5t which respectively onset with :1 gears and. Elithat are slidably movable with 'l predetermined limits along a splinet'ion driven shaft til which causes rotation of. the transmitting andrecording drums ill and in the direction indicated by the arrow on drumtil, during the scanning operations, the gears and being shiitable alongthe spline by a drum speed shift lever til, pivoted at Ella, 2, in orderto change at will the peripheral speed of rotation of the drums till andit. .As shown in li 'igs. i. and 2, gear 54 drives gear 55 when drumspeed shift lever Ed is in the position shown in the figures.Preferably, and as shown, gears M and 55 have a 1:1 ratio so that thedrums 30 and 34 may be rotated at a speed determined by the motor 50 andreduction gearing 5!, and which is well adapted for medium size drumssuch as shown in Figs. 1 and 2, and also is adapted for smaller sizedrums hereinafter referred to. If the drum speed shift lever 63 is movedto the left, as viewed in the figures, gears 54 and 56 are disengaged,and gear 55 is caused to mesh with gear 53. The gears 53 and 55 mayhave, for example, a 1:2 ratio, and thus the drums 30 and 34 will becaused to revolve at a lower speed.

An advantage of the drum speed shift arrangement is that the linearscanning speed for the drums 30 and 34 may be changed, if desired, orwhen drums of different diameters are used in place of the drums shown,as, for example, drums of a larger diameter to accommodate largerblanks, the number of revolutions per minute of the drums may be reducedto an extent such that the peripheral speed of rotation and hence thelinear scanning speed will remain the same. The gears may be so chosenthat the linear scanning speed is caused to remain approximately thesame, irrespective of the size of drums employed. For the sake ofsimplicity gear trains providing for only two changes in the speeds ofthe drums are illustrated in the drawings, since as a practical matterand within certain limits one drum speed may be used for medium size andsmaller size drums, and a lower drum speed for drums larger than themedium size drums, but it will be understood that suitable gear trainsor equivalent means may be used to give as many different speeds as maybe desirable depending upon the nature of the device and the varioussizes of the blanks to be used for transmitting and recording purposes.A friction drag device SI for maintaining a slight drag on the shaft 53,by means of a felt or other suitable element in frictional engagementwith the shaft, eliminates backlash or other jerky movement which mightbe introduced due to the action of the gears.

Secured to the shaft 58 and rotatable therewith are two driving gears 62and 63 (Figs. 1, 2 and 3), which gears respectively mesh with largerdriven gears 84 and 83. Gear 84 is secured to and drives a stub shaft 88which is Journaled in bearings at each end thereof as shown. Gear 65 issecured to and drives a stub shaft 88 journaled in bearings at each endthereof. The stub shaft 88 also carries a smaller gear or pinion 88which drives a larger gear 10, the gear II being mounted on a feed screwshaft 12 and slidably movable within predetermined limits along a splineII on the shaft (see Fig. 3) and serving to drive the feed screw 12 forcausing line feed of the recording unit 28 as recording proceeds, acorresponding line feed of the transmitting unit 23 being effected bymeans of the mechanical connection including the carriage link 42hereinbefore referred to.

Also secured to the stub shaft 86 is a. small driven gear 13. When linefeed shift lever 18, pivotally mounted at 18a, is shifted to the leftfrom the position shown in Figs. 1 and 2, it causes disengagement of thegears 69 and 18, and shifts the gear into engagement with the smallergear -l3 to decrease speed of rotation of the feed screw 12 and henceincrease the number of scanning lines per inch. For example, when theshift lever 16 is in its right hand position as shown in the drawings,the gear ratio may be such that the transmitting and recording unitsscan 100 lines per inch, that is, as the cylinder 3| rotates once thescanning assemblies will move longitudinally a distance of a hundredthof an inch, whereas when the lever 16 is shifted to the left the gearratio may be such that the number of scanning lines is increased to 120per inch. This arrangement enables the number of scanning lines per inchto be made such as to give the most desirable results depending upon thesubject matter scanned and the kind of service for which it is used. Thegear ratios of the gearing above described and the pitch of the threads12a on the feed screw 12 are so selected that the rate of longitudinaltravel of the base members 36 and 31 of the transmitting and recordingunits and the peripheral speed of rotation of the cylinder 3| cooperateto produce the proper helical scanning of the blanks on the drums 30 and34 of the cylinder. For the sake of simplicity gears providing only twodifferent rates of line feed are shown, although it is to be understoodthat suitable gearing or equivalent means may be employed to product asmany different line feeds as may be desired.

It will be noted that the line feed screw 12 is controlled through thegears 62 and 83 on the drum driving shaft 58, so that when the drumspeed is changed, as by shifting the lever 88 'from its right handposition to its left hand position, with resultant decrease in the speedrotation of the drums, for example, when larger drums are employed, thespeed of rotation of the line feed screw 12 will be decreased, and foreach rotation of the larger drums the transmitting and recordingscanning assemblies will move longitudinally the same distance as theydid with the smaller drums (for a given setting of the lever 16), andthus automatically prevent distortion which might be introduced if thespeed of rotato a shaft 84 journaled in fixed upright bearing members 83and 88 so as to be freely rotatable and also slidably movablelongitudinally within the bearings to permit entry and withdrawal of themember" from the recessed portion of the end ll of the cylinder 3|, andthereby permit ready insertion and removal of the cylinder 3| and drums38 and 34.

To facilitate the insertion and withdrawal of the member 83 there isprovided a tapered cam member 88 fixedly secured to the bearing support88, and coacting with this cam member is a second tapered cam member 8|which is secured to the shaft 84, as by means of a set screw 82. Securedto the cam member 9| is a handle 38, and when the handle is raisedupwardly as viewed in Figs. 1 and 2, this causes rotation of the cam 8|relative to the fixed cam 80, and the adjacent tapered camming surfacesof these members coact to cause the member 9| to be shifted to the rightas viewed in the figures and thereby cause lon itud nal movement of theshaft 84 and withdrawal of the bearing member 83 tion of the feed screw12 were not changed to I correspond to the changed drum speed.

The cylinder 3| has reduced ends 88 and 8| formed with internal taperedsurfaces which receive complementary bearing members 82 and 83. Themember 82 is secured to and driven by the shaft 58 hereinbefore referredto, and serves to drive the cylinder 3|. The member 83 is secured fromthe recessed end 8| of the cylinder 3|, after which the cylinder may beslid to the right a distance sufiicient to release the opposite end 88from its associated drive member 82. The cylinder may then be removedfrom th machine and replaced by another cylinder with other subjectmatter thereon, or the same cylinder may have other blanks 28 and 35applied thereto and be replaced in the machine for a subsequentrecording operation.

It will be seen that the cam member 9| has a fiat portion 8|a which,when the handle 83 has been turned to the cylinder releasing position,will cause the surface 9|a to bear against a similar flat surface on thefixed cam member 98, thereby to avoid the possibility of the member 8|accidentally slipping from its releasingposition. A compression spring86 which loosely surrounds the outer end of the shaft 84 causes themember 8| to return to the working position when the handle is turneddownwardly, the spring also causing the bearing member 83 to enter theend 8| of the cylinder thereby to insure that the adjacent end of thecylinder is properly supported during rotation of the cylinder, and alsoto insure that a proper driving connection will be maintained betweenmembers and 82. In order to minimize frictional effects between the end8| of the cylinder and the member 83, the latter may have embodiedtherein suitable bearings, such as ball bearings carried in a raceway,so as to be freely rotatable about the shaft 84.

Fixed bracket members I00 and 85 are provided, each of the bracketmembers having two arcuate supports or saddles, the inner pair ofsaddles IBM and lllla preventing the cylinder 3| from dropping when itis released from the bearings 82 and 83, and the outer pair of saddlesIfllib and "Nb of the brackets providing a convenient rest for thecylinder 3| to enable the blanks to be a plied to and removed from thedrums 38 and 34 at the beginning and termination of the reproducingoperation.

In the broader :aspect of the invention any suitable transmitting unitand any suitable recording unit may be employed. For example, thetransmitting unit may comprise a photo-rel] pickup device of a typeheretofore employed in the art for scanning subject matter to be transmitted in facsimile, such as the scanning device shown in the patent toR. J. Wise, No. 2,158,391,

issued May 16, 1939, or as disclosed in an application of R. J, Wise etal., Ser. No. 110,760, filed November 13, 1936, now Patent No.2,255,868, issued September 16, 1941. In general, such a scanning unitcomprises a lens tube lill, Fig. 2, which usually contains two lensesand an apertured plate designed and positioned with respect to eachother so that light from an exciter lamp is concentrated in a spot onthe periphery of the drum 30 and consequently on the subject mattersheet 29 thereon, the tube I04 being provided with telescopic sectionsto enable focusing adjustments. A lens tube I06 contains lenses forclirecting the beam of light reflected from the periphery of the drum 30or the record sheet 29 onto an aperture and thence to a photo-cell. Alight chopper in the form of a disc I01 is inteposed between thephoto-cell and the aperture referred to, the number of notches in thedisc I01 and the speed of rotation of the disc being variable withinwide limits depending on the desired rate of scanning, the constants ofthe communication circuits employed, and other factors. As is wellknown, the signals generated by the photo-cell, which are in accordancewith the subject matter scanned by the transmitting unit 25, areamplified and caused to operate the recording mechanlsm 26 in a mannerto reproduce on a recording blank the subject matter in facsimile as itappears on the record blank 29.

To insure high fidelity in transmitting and fine sharp definition inrecording, it is essential that the transmitting scanning apparatus andalso the recording apparatus be very accurately positioned with respectto the spacing between the scanning elements of these units and theblanks containing the subject matter thus transmitted and recorded.

Figs. 1 and 2 show suitable means for quickly and accurately adjustingthe scanning elements of the transmitting unit 25 with respect to thesurface of the transmitting drum 30. It will be noted that thetransmitting unit is mounted on a carriage H having guide members IIIwhich travel in slots in guides H2, the guides H2 being firmly securedto the frame 36. Frame III) has secured thereto upstanding bracketmembers I I3, Fig. 1, which provide bearings for a screwthrcaded rod H5having at the outer end thereof a knob H6 for rotating the rod. Thescrewthreaded portion of the rod I I5 is received within a threadedblock H8, the latter block being fixedly secured to the carriage 3B. Therotation of the rod H5, which is held against longitudinal movement bythe bracket members H3, causes the scanning assembly 25 to be movedtowards or from the transmitting drum 30, thereby to provide a properadjustment or spacing between the scanning elements and the blank 29 onthe drum, irrespective of the size of the transmitting drum employed.

The carriage Hll also carries a pointer H9, which coacts with-a plate Isecured to the support 36, the latter plate bearing indicia such as theletters A, B and C, which respectively correspond to three differentsizes of transmitting drums that may be employed. If a small drumcorresponding to size.( is to be employed, the knob H5 is turned untilthe pointer H9 is opposite the mark C on the plate I20; if a medium sizedrum is used, the scanning assembly is adjusted so that the pointer H9is opposite the mark B on plate I20; and if a large size drum isemployed, the position of the transmitting unit is acLIusted so that thepointer is opposite the mark A on the plate I20. Secured to the forwardend of the rod III is a graduated drum or vernier I22 for enabling veryaccurate adjustment of the scanning elements of the optical pickupsystem relative to the record sheet, and coacting with the Vernier is apointer I23, seen in Fig. 2, which pointer is fixedly secured to thecarriage III.

The transmitting and recording drums at and 34 are shown as having thesame diameter and being integral with the cylinder 3| in Figs. 1 and 2,but it is to be understood that either of these drums may difier indiameter from the other in order that the recorded subject matter may beeither enlarged or reduced with respect to the original, depending uponwhether the recording drum is larger or smaller than the transmittingdrum. Any distortion introduced into the enlarged or reduced subjectmatter by reason of the fact that the line feed of the transmitting andrecording drums is the same, may be obviated by taking the recordedsheet after one complete scanning operation has occurred and turning thesheet at right angles and placing it on the transmitting drum and thenre-recording the subject matter, and the re-recordecl blank will nothave introduced therein the distortion above referred to. In accordancewith another embodiment of the invention, hereinafter described, inwhich means are provided for produc ing different line feeds of thetransmitting and recording drums, the enlarging and reducing operationsare materially simplified. It is to be understood that the cylinders 30and 34 may comprise separate cylinders which abut at the adjacent innerends thereof instead of comprising a single cylinder such as the oneillustrated, and in the other embodiment referred to means are shownwhereby the separate drums may be caused to interengage with each otherat their adjacent ends,

Preferably, and as shown in Figs. 1. 2, 5 and 6, the recording unit 25is of the type disclosed in the copending application of F. L. O'Brienand P. H. Estes, Ser. No. 283,954, filed July 12, 1939, now Patent No.2,260,862, issued October 28, 1941. Such a recording unit comprises twocylindrical permanent magnets in enclosed within the unit I5I (one ofwhich magnets is shown in dotted outline in Fig. 5), one of the magnetsbeing inverted with respect to the other so that they are of oppositepolarity. Upper laminated pole pieces 152 overlap the free end of thearmature I54, and a lower pair of laminated pole pieces I56, similar inoutline to the upper pair of pole pieces, but reversed in position,extend from the lower ends of the permanent magnets I50 to overlap thearmature adjacent its connection at I58 to a U-shaped member I59, Figs.4 and 5. The upper pole pieces are secured to a non-magnetic metallicplate I", as by rivets, and the lower set of pole pieces are secured ina similar manner to a non-magnetic metallic plate I82, to which one leg01' the U-shaped member I59 also is secured, as by rivets. The top andbottom plates I" and I62, including their respective pole pieces, areclamped to the permanent magnets, as by means of bolts one of which ispassed through each of the magnets. An energizing coil I63, Fig. 5,surrounds and controls the armature I54 and is firmly held in positionwithin the unit I5I. The stylus I3 preferably consists of a U-shapedpiece of wire soldered, welded or otherwise secured to the armature I,or, ii'desired, may be formed by shaping the end of the armature so thatit will be similar in configuration to the wire stylus. The member I69is a strip of spring steel and has one end I69a that bears against anadjusting screw I64 which is threaded in the bottom plate I62. screw I64adjusts the bias of the armature I64 and stylus 33 with respect to therecording drum.

The resonant vibrational frequency of the armature I54 is preferablyhigher than the highest electrical frequency impressed on the coil I83.It will be understood by those skilled in the art that the maximummodulation frequency derived from the pickup device 25 will bedetermined by the speed of the drum 38 and the natureof the originalbeing scanned for reproduction. For example, if the drum is rotated at90 R. P. M., the unit II is preferably designed so that the resonantfrequency of the armature when vibrating freely, preferably is of theorder of 800 cycles. With the unit in operative position with respect tothe drum 34, the resonant frequency drops to approximately 650 cycleswhich is still of a value great enough to prevent the stylus 33 fromrebounding to such an extent as to affect the quality of appearance ofthe record.

The unit I5I is mounted by means of an extension I62a on the plate I62,on a slide member I66 which has tongues I61 received within grooves inguide rails I68, and the member I66 with the unit I5I is adjustabletowards and away from the recording drum 34 by means of a rod I69 havinga threaded portion I69a received within a threaded portion of the platemember I66. The rod I69 passes through a block I having tongues I16 alsoreceived within grooves in the guide rails I68. The rod I69 has a collarI11 and a knob I18 secured thereto, each of which elementsabuts againstan end of the block I15, Fig. 5, whereby when the knob I18 is rotatedthe action of the threaded portion I69a of the rod I69 will cause theunit I5I to move towards or from the recording drum 35, thereby toprovide the proper spacing between the stylus 33 and the recordingsheet, irrespective of the size of the recording drum employed. Agraduated dial or vernier I86 (Figs. 2, 4 and 5) secured to the rod I69enables very accurate adjustment of the recording stylus 33 relative tothe record sheet. Also carried by the slide I66 is a pointer I82, seenmore clearly in Figs. 1 and 2, which coacts with the plate I83 securedto the carriage member 31, the plate I83 bearing indicia, such as theletters A, B and C, which respectively correspond to three differentsizes of drums to be employed. If a small drum corresponding to size Cis to be employed, the

knob I18 is turned until the pointer I82 is oppo- I site the mark C onthe plate I83. If a medium size drum is to be employed, the unit I5I isadjusted to cause the pointer to be opposite the mark B; and if a stilllarger drum is employed,

the position of unit I5I is adjusted so that the pointer I82 is oppositethe line A of the plate I83. In each of the foregoing cases a moreaccurate adjustment is provided for by the vernier I88.

The line feed of the transmitting and receiving units is effected bymeans of a split block assembly comprising identical opposed splithalves 288, Figs. 4 and 5, which members are internally threaded toreceive the feed screw thread 120, the members being spring-pressed intoengagement with the threads of member 12a by means of four compressionsprings 26I which act between supportmembers 282 and 283, and the upperand lower portions of the members 268.

The members 262 and 283 comprise the legs of a Adjustment of thestanding lug 31a on the carriage 31. Interposed between the innertapered surfaces of the opposite ends of members 268 are twowedge-shaped members 284, the lower member 284 being secured to asplit-nut release lever rock shaft 286, and the upper wedge-shapedmember 264 is mounted on a rock shaft 281, the shaft being rotatablymounted in members 282 and 283. Member 264 on shaft 281 is operativelyconnected to the shaft 286 by means of gears 288 and 288. When thehandle 286a (Fig. l) of the shaft 286 is rotated so as to turn thewedge-shaped members 284 from the positions in which they are shown inFig. 4, rotation of these members forces the split nuts 288 apart asufllcient distance to effect their release from the threaded rod 12a,and thus enable both the transmitting and receiving units to be movedlongitudinally to any position, such as their initial starting position,after which the rod 286 is again turned in a direction such that thewedge-shaped members 284 assume the positions shown in Fig. 4 and againmake effective the feed screw 12a.

In order that there may be no likelihood of injury to the blank by thestylus 33 when a recording operation has been completed, andparticularly when the transmitting and receiving units are to be movedto their initial starting positions, a collar 2I6 shown in detail inFig. 6, is secured to the rock shaft 281, the collar 2I6 carrying a pin2I I, which pin coacts with'stop pins 2I4 and 2I5 mounted on the bracketmember 263. Pin 2 is adapted to cooperate with a spring member 2I6 andoperating member 2I1 of a stylus retractile switch 2I8 also mounted onthe bracket 263, and seen more clearly in Fig. 1. The switch 2I8controls the energizing circuit of a solenoid 228 which, when energized,causes retraction of its core 22I which has secured thereto two sideplates 22 la, and the inner movement of this core causes correspondingmovement of a pin member 222 secured thereto. the latter member beingpositioned within a slot in a post-member 223 secured to the slidableblock I15, and thus through the rod I68 and block I66 which carries thedevice I5I, causes withdrawal of the stylus a predetermined distancefrom the recording drum when solenoid 228 is energized by closure ofswitch 2I8, the limit of this retractile movement being determined bythe core 22I striking the stop member 226a on the frame of the solenoid228 when the stylus is in its proper retracted position.

The plate 226 supports the solenoid magnet structure 228 and alsosupports a bracket member 236, plate 226 being secured to a block 23Iwhich in turn is secured to the guide members I68. Bracket 236 carries adashpot 233, the plunger 234 of the dashpot being received within andactuatable by the upper end of a bracket member 235, the bracket 235being secured to the block I15. A retractile spring 236 has one endthereof secured at 231 to the bracket member 236, and the other endthereof secured to a post 238 fixedly mounted on the bracket 235, thespring serving to urge the recording unit towards the drum 34, themovement of the recording unit in this direction being limited byengagement of the inner end of the knob I18 with the end of the memberI68. When the retractile magnet 226 is energized to withdraw the stylusfrom the drum in the manner aforesaid, the spring 236 is furtherextended. The dashpot 233 eases the impact of the stylus with the drumwhen the magnet 228 is deenergized, by reason time iscaused to move tothe left. viewed in Figs. 4 and 5, under me influence of spring I",andinsodoingcausestheplungerllofthe dashpot to move inwardly, thedashpot that the stylus will gently contact the recording medium 35 onthe drum n.

The original copy sheet 12! is wrapped around the transmitting drum ll,preferably in such a manner that the top-of the copy is at the left handend of the drum when facing the-machine, the right hand edge of the copyoverlapping. the left hand edge by a slight margin. The copy may be heldin position by any suitable means, such as an elastic band or garter I"which preferably, although not necessarily, comprises a helical springin the form of an annulus such as disclosed and claimed in the aforesaidcopend of the fact that the bracket member I at this to engage the limitswitch 2, which switch op crates to open the energizing circuit of thedriving motor 50, and thus prevent injury which might otherwise becaused by overtravel of the units For producing master copies, readilyobtainablel limeograph stencil sheets may be employed. and when the unit28 is to be used for recording on one of these sheets, the knob I'll mayreadily be set so that the stylus is spaced the proper distance from thesurface of the sheet to give the desired results. In general, thesetting of ing application of R. J. Wise et al.,8er. No.

110,760, filed November 13, 1936, Patent- No. 2,255,868. As shown inFig. l, the leading garter member is advanced axially along the drum IIfrom left to right as scanning proceeds, by a garter pushing platemember I secured to the supporting frame Ill, and the trailing gartermember 240 is advanced by a second pusher plate 242 on the transmittingunit. elastic bands 240 are thus kept within a predetermined distance ofeach other and are kept immediately adjacent to the place where scanningis being effected, the bands rolling along on the copy sheet as thescanning proceeds, and holding the copy sheet tightly against the drumand preventing distorting in the optical scanning system which otherwisemight occur if the copy was not held tightly against the drum. In orderto prevent the trailing garter member 240 from jumping forward orotherwise inter fering with the scanning light ray, the plate member 2is made sufliciently wide so that if the trailing member 240 should Jumpforward,-

provided a buffer in the form of a' dashpot I" mounted on the framestructure fla the dashpot having a plunger! which is held in itsextended position by a compression spring within the dashpot cylinder.when the transmitting and receiving carriages are returned to the left,an adjustable stop member 2", shown in dotted outline in Fig. 1, securedto the carriage of the transmitting unit, engages the end oi the piston246, and as the movement of units towards the left is continued, thespring lwithin the dashpot 245 is so that it prevents undue shock on theunits. the structure also providing a suitable means for limiting theextent of movement of the units toward the left and determining adesired initial starting posi- The two the knob I18 is such that thewax, which coats the fibrous structure of the sheet, is pressed orplowed away to make the fibrous structure pervious to Mimeograph inkwithout destroyin its original form, and for this reason a Mimeographink of lower viscosity may be used.

' Where" hectographic carbon paper is emplayed," a sheet of hectographcarbon paper is placed over a sheet of hard finish white paper and thecombination placed on the recording drum in such manner that the whitepaper is next to the drum. The hectographic carbon paper plus the whitepaper underneath may have a thickness of approximately .005 of an inch,and for recording with such paper the tip of the stylus may be spacedthe proper distance, for example, of the order of .010 of an inch awayfrom the surface of the recording drum when the magnet I63 isdeenergized.

In the embodiment of the invention illustrated in Figs. 7 to 9 of thedrawings, the transmitting and recording drums 30a and 34a compriseseparate cylinders so that enlargement or reduction of the reproducedcopy may more readily be obtained, and without the necessity ofemploying long cylinders such as 3| in Fig. 1, which when machined orformed to provide drums of different sizes are relatively expensive. Thetransmitting cylinder 30a, which in the form shown in Fig. 7 is largerthan the recording cylinder a, has its inner end 302) formed with areentrant or flanged portion such that it receives the end Nb of therecording cylinder 34, so as to be in driving relation therewith asindicated in dotted outline in the figure. As illustrated, the relativesizes of the transmitting and recording drums will cause the recorded ormaster copy to be reduced with respect to the original copy. It will beunderstood, however, that the smaller or medium size drum am may be usedfor transmitting and the larger drum for receiving, so that an ention ofthe units. At the left. hand endof-"t'he frame 20, as shown in Figs. 1and 2, is a limit switch 2 which is engageable" actuating member 248secured to the e of the recording unit 20. If the apparatus "is notstopped after scanning has been completed, continued line feed travel ofthe transmitting largement oi the original is produced. Also, ifdesired, the transmitting and reconiing drums may have the samediameter, while retaining the advantages of using separate drums orcylinders for transmitting and recording purposes.

The embodiment illustrated in Fig. 7 also has the advantage ofreproducing the original copy, which may be reduced or enlarged withrespect to the original, without introducing distortion in the recordedcopy and thus obviating the step of re-recording the copy to eliminateany distortion that may be introduced with the apparatus of Flg's'.l and2; For this purpose, separate feed screws are provided for thetransmitting and recording units, the line feed screw shaft 250 beingdriven from the motor and gears shown on the left hand portion of Fig. l(which are indicated at I) in Fig. 7 in which the driving units are mom;as enclosed within a casing 249) and and recording units will cause themember at an, is provided for the recording unit :6. 0n

the righthand end of the feed screw shaft 250 are-three. gears 260, 2"and 262 which engage a spline 25Gb on the shaft, the gears beingshiftable along the spline by means of a feed screw shift lever 264which is pivotally mounted at 265 to the apparatus frame. The gears 260,2 and 262 are adapted respectively to mesh with driven gears 210, 2H and213 to provide different driving ratios for the shaft 212.

With the lever 264 in the position shown in Fig. 7, the feed screw 212'for the recording unit 26 is driven at a lower rate of speed than thefeed screw 250 of the transmitter unit so that the reproduced record ormaster copy will not have introduced therein any distortion, the numberof scanning lines per inch being increased thereby to correspond to thedegree of reduction of the subject matter as caused by the smallerdiameter of the recording cylinder a. If the line feed shift lever 264is shifted, as by moving the handle 264a to the left, so that gear 26lmeshes with gear 2, a 1:1 ratio between the feed screw shafts 250 and212 is obtained, and thus the apparatus is adapted to operate with arecording drum of the same size as the transmitting drum. Furthermovement to the left of the handle 264a of the shift lever causes thegear 262 to mesh with gear 213, and thus the rate of feed of the screw212 is higher than the screw 250, thus enabling a larger drum to be usedfor recording than is used for transmitting, thereby to enlarge therecorded subject matter, the rate of increase of the line feed of thescrew 212 being such as to compensate for the enlargement of therecorded copy and thus prevent distortion. It will be understood that asmany different gear ratios between the feed screws 25!! and 212 may beprovided as may be desirable or necessary depending upon the differentrelative sizes of the transmitting and recording drums employed.

A split nut release unit 25! for the transmitter 25 is provided, whichunit may be substantially the same as that shown in Figs. 4 and 5 forthe recording unit, and rotation of the lever 256, by

means of the handle 266a, will cause the split nut assembly to bedisengaged from the threaded portion 250a of the feed screw 25!] toenable the transmitting unit to be moved along the guide rods 22 and 23to any desired position, while the recording unit 26 is independentlymovable since it has a split nut release unit like that shown in Figs. 4and 5 of the drawings.

In addition to the use of Mimeograph stencil I sheets, hectograph carbonpaper, and the like, the recording unit is adapted to produce a mastercopy on a metallic planographic printing plate or sheet of zinc,aluminum or other suitable material, various of which plates or sheetsare wellknown, and from which any desired number of copies may beprinted. In general, planographic printing from these plates dependsupon the immiscibility of oil and water and the preferential retentionof the greasy image-forming substance by the image areas and a similarretention of an aqueous dampening fluid by the non-image areas, theplates being treated in such manner that they are sensitized" to ink.After the image has been delineated on the plate, as by means of therecording unit 26, the non-image areas are desensitized and the plateprepared for printing by suitable treatment with various solutions knownin the art. One form of planographic printing sheet suitable for thepurpose is an aluminum sheet prepared in the manner disclosed inthepatent to G'. s. Rowell, No. 2,129,071, issued September 6, 1938, one ofwhich sheets is indicated by the reference numeral 215 in Figs. 7 to 9.Preferably, and as shown, the plate has each end thereof escalloped toprovide projecting ears 216 for securing the plate on a printing drum ofan Addressograph or Multigraph machine, preparatory to printing copiesfrom the plate, in such manner that the plate and the holding device onthe printing drum have mutually overlapping portions occupying the samecylindrical surface thereby to provide a continuous engagement of thesurface of the inking roller of the Multigraph or Addressograph machinewhen copies are being reproduced from the master copy or plate, asdisclosed in the patent to W. R. Allen et al., No. 1,967,221, issuedJuly 24, 1934.

In the form of recorder shown in Figs. 7 to 9, the planograph printingsheet 215 is applied to the recording drum 34a with a sheet of paper orother suitable transfer medium carrying a greasy ink-retainingimage-forming substance which may, if desired, have coloring matterincorporated therein so as to make the image readily visible on theprinting sheet. It will be understood that the metal sheet and transfersheet may be placed on a flat bed or platen during scanning if used infacsimile apparatus of the fiat bed type. With the cylindrical form ofrecording platen, the sheet 211 is placed on the outer periphery of thesheet 215, the sheet 211 being adapted to be engaged by the percussionstylus 33 as the scanning operation proceeds so as to produce on thesurface of sheet 215 a facsimile copy of the transmitted subject matter.It will be noted that the leading edge of the carbon sheet is placedbeneath the trailing edge of the sheet 215, as shown in detail in Figs.8 and 9. The sheets are held snugly against the surface of the recordingdrum in proper scanning position by means of a garter member 216 whichpreferably comprises a helical spring 2400 in the form of an annulus,the spring being surrounded by short lengths or beads 219 of rubbertubing or the like, the rubber tubing preventing the convolutions of thecoil spring 240a from bearing on the surface of the carbon paper 211 andthereby prevent accidental pressure on the carbon paper from producingmarks on the sheet 215 due to the rolling action of the garter. It willbe appreciated that any mark accidentally made on' the sheet 215 by theaction of the garter 218 would result in undesirable marks or smudgingon the printing plate. When a sheet such as the aluminium sheet 215 isemployed, and particularly when the sheet is shaped or preformed in amanner hereinafter described, only one garter member need be employed,providing this member is caused to be maintained at a place adjacent tothe place where the printing plate is being scanned by the recordingstylus. To effect this, the recording unit has mounted thereon a plate280 which serves as a pusher and causes the garter member to rollaxially along the recording drum as the scanning operation proceeds.

A metal planograph printing sheet or plate, such as the aluminum sheet215 shown in Figs. 7 to 9, is appreciably stiffer than paper, stencil orhectograph' sheets, and it is advisable to shape or preform the metalsheet before applying the same to the recording drum in order to preventcreasing of the sheet and to insure that neither the leading nor thetrailing edges of the sheet will project beyond the periphery of theremainder of the sheet, which might cause vibration of or injury to thestylus 32 during the recording operation. A method of and apparatus forpreforming such sheets so that the sheets including the leading andtrailing ends or edges thereof will lie snugly against the recordingdrum is shown in Figs. 10 to of the drawings. Referring to thesefigures, there is shown a preforming or curling apparatus comprising agenerally flat rectangular base member 300 which may be made from wood,Bakelite, metal or other suitable material, the base member having feetor legs 30i which preferably are of resilient material to avoid marringof the desk, table or other support on which the preforming apparatus issupported. Rigidly secured to the base 300 are two side bracket members302, which members in turn support upstanding bracket or bearing members303.

As seen more clearly in Figs. 12 and 13, the members 303 each has aslotted portion 303a, these slotted portions comprising bearings for ashaft 305 that extends transversely across the top of the preformingunit, the shaft having thereon a coating of hard rubber or othersuitable material which forms a roller 305 for engaging the uppersurface oi the metal printing plate during the preforming operation. Theshaft 305 has a handle 301 by means'of which the roller 305 may readilybe rotated within the bearings formed by the slotted portions 303a ofthe members 303. Shaft 304 also has secured therei to, as by set screws,two collar members 308. Rotatably mounted on shaft 305, and adjacent tothe inner sides of the collar members are link members 309 which carry aguide roller 310 that cooperates with the roller 305 during thepreforming operation. Disposed adjacent to the outer sides of the collarmembers 308 are link members 3 which are loosely mounted on the shaft305, the link members each carrying at its outer end a latch member 312.The latch 312 has notches or locking portions 312a and 3122) which coactwith a locking member 3l3 secured to the bracket 303, in order to lockthe shaft 305 and roller 305 in either of its two operative positions,one such position being shown in full line in Figs. 12 to 15, and theother position being shown in dot-dash line in Fig. 12.

Mounted on the base 300 are two angle iron members 314 which serve asguide rails for carrying a carriage 3l5, the carriage having two angleiron members 316 secured thereto to insure that the carriage will slideeasily in the guide rails 3M. Secured to the carriage 3l5, as byglueing, is a pad 320 which preferably is composed of sponge rubber. Inthe position shown more clearly in Figs. 12 t 15, the shaft 304 is inposition to curl or preform the aluminum sheet 215, at which time theroller 305 is forced into the upper surface of the pad 320 a suflicientdistance to cause the necessary bending force to be exerted on theprinting plate 215 when it is passed between the roller 305 and thesurface of the pad 320. Fig. 14 shows the beginning of the preformingoperation in which a flat metal sheet 215 has been placed on the uppersurface of the pad 320 with the leading and of the sheet passed underthe guide roller M0 and between the forming roller 305 and the adjacentsurface of the pad, this being effected by turning the handle 301 so asto rotate the roller 305 in the direction indicated by the curved arrowin Fig. 14. Continued rotation of the roller 305 causes the pad and itscarriage to travel in a longitudinal movement in a direction indicatedby the straight arrow in Fig. 14, the carriage 315 sliding along on theguide rods 3" at this time.

Once the leading edge of the sheet 215 is caught between the roller 305and the pad, the sheet is formed automatically as the handle 301 isretated, this being effected by the pressure exerted by the roller 305on the sheet 215 and the coacting surface of the pad 320. As therotation of roller 305 is continued, this causes the sheet 215 to passbetween the under surface of the roller and the surface of the pad, andin thus passing the sheet is bent and given a desired smooth arcuateconfiguration throughout as shown in Fig. 15, the pressure exerted bythe roller 305 on the sheet and the resiliency of the pad being sochosen as to provide a curvature of the sheet such that it substantiallycorresponds to the outer periphery of the recording drum on which itsubsequently is mounted.

After the recording operation has been effected on the printing plate,it is desirable to straighten the sheet 215 so that it is flat as itoriginally was, and this may readily be effected by the preformingapparatus in the following manner: The latch members 3l2 are releasedfrom the full line position shown in Fig. 13, after which the shaft 304is slid to the upper end of the slot 303a to a position shown indot-dash outline, and the latch member 3I2 rotated by hand so that itslocking portion 312a is in engagement with the locking member 3I3, atwhich time, due to the upward slant of the slot 30311, the pressureexerted by roller 305 on the pad 215 is reduced to a value such thatwhen the curved sheet 215 is inserted beneath the guide roller 310 andthe roller 305, and the handle 301 again turned in the same direction aswhen the sheet was preformed, just sufficient pressure will be exertedby the roller 305 to flatten or straighten the sheet 215, it beingunderstood that the curved sheet is placed on the pad 215 with its outerarcuate surface upwards.

The position of the roller 305 during the straightening operation isshown in dotted outline in Fig. 12, at which time the roller exerts a.comparatively light pressure on the surface of the pad 305, thispressure being just sufficient to straighten the sheet 215 withoutintroducing a. reverse curve therein, the sheet thus being restored toits original flat condition whereby it may be placed on a printingmachine for reproduction in any suitable manner. Preferably, and asshown, four upstanding stop members 322 are secured to the base 3|5 ofthe pad carriage to limit the extent of travel of the pad in eitherdirection, the travel of the pad being sufllcient to both preform andstraighten the sheet 215.

In the embodiment illustrated in Fig. 7, the transmitting and recordingdrum have complemental projecting and recessed portions at the adjacentends 30b and 3417 such that the inner end of each drum supports theadjacent inner end of the other drum in driving engagement. However, ifdesired, a separate bearing or support may be secured to the base 20,having arcuate bearing surfaces which provide a support for the adjacentends of the transmitting and recording drums thereby to insure that theaxis of rotation of the drums will remain straight and true.

Fig. 19 of the drawings illustrates diagrammatically a preferredelectrical system which may be employed in connection with thetransmitter and recorder apparatus, although, as hereinbefore set forth,other known electrical systems suitable for transmitting and recordingin facsimile may be employed, depending upon the purpose for which theapparatus is to be used, such systems including the systems disclosed inthe aforesaid Patents Nos. 2,255,868 and 2,260,862.

In the system shown in Fig. 19 only one photocell 350 need be employed,an inversion of the transmitted signals being effected in the amplifiercircuit in the manner hereinafter described. It will be understood thatthe photocell 356 receives modulated light from the original copy to bereproduced, and that an alternating current output is derived from thephotocell by the use of a light chopper driven from a motor (not shown),which output is amplified by the amplifier 35! which may compriseseveral stages of amplification. Embodied in the amplifier is a gaincontrol 362 for the purpose of adjusting the amplitude of the signalswhich are supplied to the recording unit, and as shown in Fig. 1, thisgain control may be mounted on the transmitting unit 25 so that it isreadily accessible to the operator of the machine.

The output of the amplifier 35I is connected by a double-poledouble-throw switch 355 to the primary of a transformer 356. When therecorder is to be used for receiving signals from the transplied to therecorder to be adjusted in accordance with the characteristics of theamplifying apparatus employed. The secondary winding of the transformer356 is connected to the grid of a thermionic amplifier 358 whichpreferably has a high amplification factor. The type 6K6 tube is anexample of a vacuum tube suitable for the purpose. The output of thetube 358 is connected to the primary of a transformer 366, the secondaryof this transformer being connected to a thermionic rectifier tube 36l,the type 84 tube being an example of a rectifier suitable for thepurpose. The output circuit of the rectifier tube controls the grids oftwo tubes 362 and 363; the type 6L6 tube is an example of tube for thepurpose.

The plate circuit of the tubes 362, 363 may be connected to therecording unit 26 by a series circuit comprising conductor 364,double-throw switch 365 when in the position shown in full line in thefigure, resistance 361, milliammeter 368, through the recording device26, and thence through resistance 316 and conductor 31! to Dositive Bbattery 312. With the switch 365 thrown to the position indicated indotted lines in the figure, a parallel connection of the plate circuitof tubes 362 and 363 is provided, one branch of which includesresistance elements 316 and conductor 31I to battery 312, the otherbranch comprising conductor 364, lower blade of switch 365, conductor366, recording unit 26, milliammeter 368, and resistor 316 to ground at318. A condenser 316a is bridged across resistance 310 in order to shapethe signals so as to provide a square-front signal shape, which isdesirable to insure prompt action of the stylus 33 of the recording unit26. These alternative plate circuit connections, as determined by theposition of the switch 365, enable either a positive copy or a negativecopy to be produced by the recording unit 26, as explained in thefollowing description of the operation of the circuit.

When signals are transmitted from a positive original for reproductionby the recorder as a positive copy, the carrier signals received at therecording amplifier from either the transmitter 25 directly or from theline L are further amplified by the tube 358. As above stated, theoutput of this tube is rectified by the tube 3H, and the rectifiedsignal is placed across a resistor load 380 in such manner that negativepotential is applied to the grids of the tubes 362 and 363, the positiveterminal of the resistor 386 being connected, by means of a switch 38!when in the position shown in the drawings, through a resistor 382 to asource of positive potential 383. With the switch 365 in the full lineposition shown in the figure, the coil of the recording unit 26 isplaced in the plate circuit of tubes 362 and 363 in series with the lusB battery 312, the resistor 361 being an additional resistor which isinserted, with the switch in the full line position, to reduce the howof plate current when producing a positive recorded copy from a,positive original blank.

An incoming signal caused when the transmitter scans the'white portionof the original blank, known as the background or non-marking signal,causes a negative potential to be placed on the grids of tubes 362 and363, which overrides the positive potential'placed thereon by thebattery 383, and reduces the plate current to a minimum through therecording unit, at which time th stylus 33 is out of contact with therecording medium. When the incoming signal, as from a black character inthe original copy, is lower in amplitude, the net potential on each ofthe grids of tubes 362 and 363 will be positive due to the preponderanceof the positive battery 383, causing plate current to fiow which, inturn, actuates the stylus against the recording blank, thus producing amark in response to the signal from the transmitter. In this manner apositive copy is produced on the recording medium from a positiveoriginal at the transmitter, or if desired a negative copy may beproduced on the recording medium from a negative original at thetransmitter, although in the case of stencils it is desirable totransmit from a positive and reproduce a positive.

With the switch 365 thrown to the position indicated in dotted lines,the reproduced subject matter is inverted, as between the original andthe recorded copy, since the recording unit 26 is removed from the abovementioned series arrangement of the plate circuit, and connected betweenthe plates of tubes 362 and 363 and ground at 318, and in its placebetween the plates of the tubes 362 and 363 and the plus B battery 312is inserted a resistor or lamps 316, as shown. With the signals from thebackground or white portion of the original copy at the transmitterrectified as before, a negative potential is placed on the grids oftubes 362 and 363, which negative potential prevents any flow of platecurrent through the tubes and allows the current from battery 312 toflow through the resistance units 316, conductor 364, lower blade ofswitch 365, conductor 366, and the recording unit 26, milliammeter 368,and resistor 310 to ground at 318. When the light beam at thetransmitter scans the dark portion of the original copy, the resultantcarrier signal when rectified by tube 36| is not sufficient to block thefiow of plate current of tubes 362 and 363, which plate current nowfiows through the resistors 316 from the battery 312.

This path through the tubes, being of relatively low resistance, divertspractically all of the current passing through resistors 316, away fromthe path to ground containing the recording unit 26, and the residualcurrent through the re-- cording unit 26 is not sufficient to cause thearmature to be energized for marking purposes. Under this conditioningthe switch 365 removes the resistor 361 from the circuit of unit 26 soas to preserve the correct resistance ratios of the network.

With the switch 38l thrown in the position shown in Fig. 19, the circuitis particularly adapted for reproducing stencils in which a triggeraction is desired so that all blows oi the percusslcn stylus 33 will beequal in intensity regardless of the density of all marks above apredetern'iined level on the original copy sheet from which the signalsare transmitted. Where, however, it is desired to produce hall? tonework, as by using carbons and the like, the switch may be moved to itsother position to connect the grids of the tubes 362' to ground throughthe resistor 385, and thus change the large positive bias on the gridsof tubes 362 and 363 to a substantially zero bias, and the circuit isthen especially adapted for producing half tone work on the recordedcopy.

Fig. illustrates diagrammatically an electrical system for placing therecorder-transmitter unit in operation and controlling certain movementsof the apparatus. A source of alternating current power supply for thesystem is connected through a line switch 390 to the various elements ofthe control system. When the switch 399 is closed, it will be seen thatan energizing circuit is provided for the stylus retractile solenoid229, this circuit comprising conductors 392 and 393, solenoid 229,conductor 394, break contact 395 and armature 396 of relay 391, andconductor 398 to the other side 409 of the power supply circuit, thisarrangement automatically causing retraction of the recording stylus.When the start button is pushed inwardly, a circuit is completed fromone side 400 of the power circuit, through the momentarily closedcontacts of the start button, thence through the relay 391, normallyclosed contacts of the stop" button, normally closed contacts of thelimit switches 249 and 425, to the other side 392 of the power circuit.Relay 391 operates and locks up through its inner armature 4M and makecontact 492 and conductor 398. Relay 394, in operating, also closes atits outer make contact 493 a circuit through armature 396, conductor 39Band the driving motor 59 for energizing the driving motor to start themachine in operation, the retractile solenoid 229 being deenergized bythe open circuit at contact 395 of the relay 391, the relay 391remaining locked up during the scanning operations.

When the split unit release 1ever shaft 296 (Figs. 1 and 7) is rotatedin a direction to re lease the split nut unit hereinbefore referred to,as when scanning is completed, this causes rotation of the shaft 291 andactuates the switch 2l9 in a direction to close its contacts 2l8.Closure of the contacts 2! completes a circuit from one side of thepower supply 490 through the contacts, conductor 495, retractilesolenoid 229, and conductor 393 to the other side 293 of the powercircuit, thus energizing solenoid 299 and causing withdrawal of therecording stylus 33.

Opening the contacts of the "stop button, by

pushing the button inwardly, opens the holding circuit for the relay391, and release of its outer make contact 493 opens the driving motorcircuit and stops the machine. In the event that the machine is notstopped by the stop button after a given piece of subject matter hasbeen scanned, it will automatically be stopped by opening of thenormally closed contacts 243 of the carriage limit switch when engagedby the stop member 249 mounted on the recording unit The recording unitmay be operated by signals from a distant point, as stated hereinbefore,and when this is done, the control apparatus disclosed in Fig. 20 may,if desired, be ope-rated by remote control signals in any dei'ed manner,such, for example, as in the mannor of the remote control apparatusdisclosed Fig. 9 of the aforesaid O'Brien et a1. Patent 2,260,862, ifdesired, the transmitter ma also be employed to transmit signals to theline L in 19 for the switch 355 or, if desired, both of these switchesmay be closed so that the transmitter transmits signals to the line Land also to the recorder unit 26.

Figs. 16 and 17 disclose a modified form of means for holding thetransmitting and recording cylinders 50 that in certain instances it isunnecessary to adjust the position of the transmitting and recordingunits towards and from the axis of rotation of the drums to compensatefor drums of different diameters, Referring to Fig. 16, referencenumeral 459 designates generally a transmitter-recorder of the charactershown in Fig. 1 or Fig. 7. To hold the drums in proper scanningposition, there are provided upstanding bracket or bearing members 45land 452 which hold the opposite ends, respectively, of the cylindergenerally designated at 456, the bracket members being secured to thebase 29 of the transmitter-recorder unit. The driving shaft 453 may bedriven from the driving gear mechanism illustrated in detail in Fig. 1except that the direction of rotation of the shaft 53 must be such thata friction drive roller 454- secured to and rotatable with an end of theshaft will drive the cylinder 456 in the direction indicated by thearrow on the cylinder.

The cylinder 456 has at the left hand end thereof, as viewed in Fig. 16,a peripheral grooved portion 451, preferably V-shaped as shown, withwhich the friction drive roller 454 engages, thereby to prevent slippagebetween the driving roller 454 and the driven cylinder 456, The cylinderhas studs or shafts 459 projecting from the ends thereof, which shaftsare rotatably supported in slotted portions 45m and 452a of the supports45| and 452. Each of the bracket members 45l and 452 carries an assemblycomprising a lever 499, the lever being pivotally mounted to its bracketmember at 46l,,and carrying an idler roller 462 rotatably mounted on astud. 463 secured to the bracket 469. A tension spring 464 has one endthereof secured to the lever 369, and at the other end is anchored to apin 465 secured to the bracket member, thereby to insure that thecylinder 456 will be maintained against the friction drive roller 454 atone end of the cylinder, the other end of the cylinder being heldagainst an idler roller 455 mounted on a stud 455a secured to thebracket member The cylinder readily may be inserted in the slots 45laand 452a, by moving the levers 469 outwardly so that the projectingshaft portions 458 of the cylinder can enter the slots 45M and 452a fromthe top, after which they are slid in the slots until the cylinder abutsagainst the driving roller 454 and idler roller 455. When a cylinder isemployed in which the transmitting and recording drum portions thereofare of the same diameter, it is unnecessary to adjust the transmittingand recording units towards and from the axis of rotation of thecylinder, since the transmitting and recording drums are held in theproper position with respect to the scanning elements by means of therollers 454 and 455 bearing on the peripheral end portions of thecylinder. By means of this arrangement, the apparatus readily is adaptedto receive cylinders of'diiferent diameters since the several scanningpositions of the shafts 458 of the cylinders in the slots 45la and 452aare automatically determined by the diameters of the particularcylinders employed. The cylinders may be driven by means of gearssecured to the driving ends of the cylinders, instead of the frictiondrive vroller shown, but an advantage of the friction drive on theperiphery of the cylinders is that the peripheral or linear scanningspeed may thus be caused to remain the same, irrespective of thediameters of the cylinders employed.

Fig. 18 shows how transmitting and recording drums of differentdiameters, respectively, may concurrently be employed with thearrangement of Figs. 16 and 17. When the recording drum 4" is smallerthan the transmitting drum 415, a ring or collar 48!) havin a peripheralV-shaped groove "I is secured to'the end of the recording cylinder 41!in any suitable manner, as by a set screw or by having the collar 480integral with the recording drum. Where drums of different diameters arethus employed, it may be appreciated that one of the units, for example,the recorder, will have to be adjusted by means of the adjusting screwsI18 and I80 So that the armature 33 of the recorder is in the properspaced relation with respect to the recording blank on the drum 4'". Ifthe drums are reversed, that is, if a smaller drum is used fortransmitting and a larger drum for recording. then the member 480 isapplied to the shaft 458 at the transmitting end of the apparatus, theV-shaped groove 48l enabling the cylinder 415 to be reversed so that thesmaller drum may be used for transmitting and the larger drum forrecording, this portion 45I coacting with the driving roller 454 forrotating the cylinders at the proper speed to effect the desiredscanning action.

In order to save operating time and to cause the scanning operation bythe transmitter to stop approximately as soon as the ubject matter onthe original blank has been scanned, irrespective of the length of theblank, a switch 425, Figs. 1, 2 and 20, is provided, which switch may,if desired, be mounted on the travelling carriage of the recorder unit25, the switch being connected, as by a flexible cord, in series withthe carriage limit switch 248 in the manner diagrammatically shown inFig. 20. Coacting with the switch 425 is an actuating unit 425 thereforwhich, as shown in Fig. 1, may comprise a collar or sleeve member 42!that has a relatively close fit with the guide rod 23 on which it ismounted, the unit 425 being slidable longitudinally along the guide rodand thus readily settable to different machine stopping positionscorresponding to various positions of the transmitter at the time thesub-- ject matter on the transmitting blank has been completely scanned.Preferably, and as shown, the adjustable unit 425 has a spring member429 carried thereby, which spring member resiliently engages in a spline435 in the guide rod 23, thereby to prevent rotation of the unit aboutthe guide rod and also to frictionally engage the guide rod so that theunit will remain in any adjusted position. Connected at 432 to thecollar 42'! is an extending portion 433 in the path of travel of theswitch 425, the member 433 carrying an adjustable switch-actuating pinor member 434. When the transmitter has completed its desired scanningoperation, the line feed movement of the carriage of the recording unit25 will cause the switch 425 to engage the pin 434 which opens thenormally closed switch contacts and thus automatically stops the drivingmotor 55 and the transmitting and recording operations.

The unit 425 is manually set by the operator prior to the scanningoperation of any given subject matter, and in order to determine readilythe setting to which the unit should be placed, there are providedcorresponding calibrated scales 435 and 431, the scales preferably beingsecured to the base member 20. The cal brations on the scale 431correspond to the calibrations on the scale 435, whereby the operatormay place the subject matter sheet on the transmitting drum and visuallydiscern the proper mark on scale 435 which represents the end of thesubject matter on the blank to be scanned so that she can set the unit425 to the corresponding mark on the scale 431, a pointer 438 on theunit facilitating the setting of the unit to the proper position. Ifdesired, the carriage limit other machines, and insures that the machinewill stop at the proper time without the operators attendance. A furtheradvantage lies'in the fact that with subject matter blanks of differentlengths (as measured longitudinally along the transmitting drum), andparticularly when a sheet of relatively short length is placed on thetransmitting drum, the automatic stop switch 425 insures that scanningwill not proceed along the drum beyond the limits of the paper of theblanks which, if permitted, would cause an optical unbalance, as whenthe light beam leaves the paper and scans a portion of the drum, thusresulting in unwanted marks on the reproduced copy. With the arrangementabove described, it makes little difference what the length of the blankmay be on which the subject matter to be transmitted appears, and theblanks do not have to be made uniform in size and can always be placedat the same starting point on the drum, or if, due to carelessness ofthe operator, the blank is not placed at the proper starting point onthe drum, nevertheless the scanning action will be stopped as soon asthe subject matter on the blank has been completely scanned. Indicatingmeans, such as arrows z and :c' on the base 20, Fig. 1, facilitateproper placing of the blanks. It will be understood that the relativepositions, and manner of mounting, of the switch unit 425 and itsactuating unit 425 may be varied or interchanged, and that either of theunits may be mounted on the transmitter carriage or other suitablesupporting element to provide relative movement between them, and may beemployed in connection with the various modifications oi the apparatusof Fig. 1 such, for example, as illustrated in Fig. 'I.

With regard to various elements of the electrical system forinterconnecting and operating the transmitting and recording units, itis highly desirshle that the voltage of the power supply for variousones of such elements be maintained within very close limits in order togive the best operating results. To provide a voltage regulator capableoi maintaining a constant voltage in regard to the total power suppliedto the trans mitter-recorder would involve considerable expense, since arelatively large voltage regulutor for such purpose would have to beemployed. Various of the elements, however, such as the driving motor 56and the relays and magnets in the control circuit shown in Fig. 20, willoperate satisfactorily notwithstanding variations in the voltage of thecurrent supplied to them, whereas with other elements, such as thephotocell b and the amplifying, rectifying and recording units of thecircuit of Fig. 19, the supply voltage should be maintainedsubstantially constant at all times. As indicated in these two figures,the power supply circuit may be divided in such manner that only theextremely sensitive elements. such as those of Fig. 19, are suppliedwith power through a voltage regulator 440, a separate line switch Ienabling this portion of the circuit to be controlled independently ofthe power supply for the circuit of Fig. 20.

As shown in Fig. 19, the voltage regulator 0, which may be any one ofseveral suitable types known in the art, is connected to a power pack442, the power pack having extending therefrom cables 3 and l forsupplying current of the proper voltage, both alternating and direct, tothe various units of Fig. 19. As is well known the power pack 2, whichreceives a source of alternating current supply of constant voltage fromthe voltage regulator 440, has the necessary transformers, rectifiersand voltage dividers to supply the various different currents andvoltages to the system. The cable 3, for example, transmits direct andalternating currents of proper constant voltages to the photocell 350and associated amplifier equipment 35l and the cable 444 transmitsalternating and direct currents of proper constant voltages forenergizing the various other amplifying and rectifying units in Fig. 19and also the recording unit 26. Direct current of the proper voltage isapplied to the plate circuits of the various tubes, whereas thefilaments or heaters of the tubes may be energized with alternatingcurrent of the proper voltage, these sources of current beingdiagrammatically indicated in the figure by means of battery symbolswhich, it will be understood, represent the various sources of currentobtainable from the power pack 2.

By means of the split circuit arrangement indicated in Figs. 19 and 20,a voltage regulator Ii which is appreciably smaller in size may beemployed than would be the case it the voltage regulator supplied thecurrent for the entire electrical system, and the cost, of the desiredvoltage regulation is appreciably reduced. The voltage regulator isespecially important in connection with the operation of the recordingunit oi the character disclosed, since when making stencils or printingplates from which copies may be made, the system provides a trigger"action for the unit 28, thereby to prevent marking 01' the recorded copyunless a signal of given density is transmitted and to prevent currentin excess of a predetermined amount from being applied to the recordingunit, and the percussion stylus 33 will not be actuated falsely due tounwanted marks below a predetermined signal level on the originalsubject matter blank and, moreover, will exert substantially the samedegree of striking power on the stencils or printing plates irrespectiveof the density of the marks on the original subjects matter blank solong as such marks are above a predetermined level. inasmuch asthesubject matter transmitted and the stencil or printing plate reproducedon the transmitter-recorder unit may be secured on a common drum orcylintier or on drums or cylinders mechanically interconnected wlth eachother, no synchronization problem is presented and a faithful copy inexact register will be produced on the stencil sheet or printing plateas scanning proceeds. Prior to a scanning operation the photoelectricpickup device 350 may be balanced on a selected portion of the originalblank, as on a white portion thereof, by adjusting the gain control 352on the pickup carriage, correct balance being indicated by apredetermined deflection of the milliammeter 368. Also, proper balancemay b effected by directing the beam which is projected into thephotocell 350, upon the lightest portion of the original which is to beproduced, for example, a pencil mark, and adjusting amplifier control sothat the stylus just marks. With this setting anything lighter in shadethan the portion of the original selected for the balancing operationwill not operate the stylus 33 of the recorder.

In general, when preparing stencils or printing plates from which copiesmay be made, it is not desirable to transmit signals directlyproportional to the shading of the picture or other original subjectmatter transmitted, but rather to transmit a signal of the sameintensity for the lightest mark as for the heaviest mark, thisequalization of signals being desirable to avoid a tendency for dropoutsin the case of light or faint signals and a. tendency for the recordingstylus to tear or mutilate the recording medium in the case of a heavyor strong signal. This equalization is obtainable in the system of Fig.19 by placing on the grids of the output tubes 362 and 363 a heavypositive bias, the rectified signal from the photocell being poled insuch manner than an incoming signal will overcome by a large margin thispositive bias, and cause a resultant large negative bias to be placed onthe grids of these output tubes, thus reducing the plate cur rent ofthese tubes to a minimum. When the light from the exciter lamp in thetransmitter is focused, for example, on the white portion of theoriginal subject matter, the reflected light causes no current to flowthrough the recording unit 2 in the plate circuit of the output tubes,whereas the reflected light from the black mark above a predeterminedlevel on the original copy causes a decrease in the signal to such anextent that the rectified voltage will not overcome the positive gridbias on the output tubes and will allow the plate current to reach amaximum, The current limiting resistor 310, which for ordinary usage mayhave a resistance of the order of flve thousand ohms, may be of thereplaceable type and can b changed from time to time if it is deemednecessary. The equalization referred to above allows a change in platecurrent from approximately zero level to maximum with a very slightdecrease in the amplified signal.

While the invention has been described and explained in detail inconnection with the various illustrative embodiments thereof, it is tobe understood that the invention may be embodied in other forms and thatthe invention is not limited except as indicated by the terms and scopeof the appended claims.

:What is claimed is:

'1. In. apparatus for facsimile telegraphy, the combination of means forreleasably engaging and axially supporting interchangeable messagecylinders having substantially different diameters respectively forholding blanks of different sizes during scanning operations, drivingmeans operable at a predetermined constant speed for rotating thecylinder at the time engaged by said supporting means, a scanning unithaving means for scanning the blank on said cylinder, said scanning unitbeing molded on a carriage, means for progressively moving said carriagelongitudinally along said cylinder during rotation thereof to provideproper line feed of the scanning unit, and means for insuring that thescanning means of the unit will be properly positioned with respect tothe blanks notwithstanding that said cylinders of different diametersare employed, said last named means comprising means on. said apparatusfor enabling relative adjustment of said scanning unit and the cylinderto be scanned. to any one of different predetermined positions withrespect to the axis of rotation of said cylinder, corresponding to thediameter of the particular cylinder to be scanned.

2. In apparatus for facsimile telegraphy, the combination of means forreleasably engaging and axially supporting interchangeable messagecylinders having substantially different diameters respectively forholding blanks of different sizes during scamiing operations, drivingmeans operable at a predetermined constant sp ed for rotating thecylinder at the time engaged by said supporting means, a scanning unithaving means for scanning the blank on said cylinder, said scanning unitbeing mounted on a carriage, means for progressively moving saidcarriage longitudinally along said cylinder during rotation thereof toprovide proper line feed of the scanning unit, means for insuring thatthe scanning means of the unit will be properly positioned with respectto the blanks notwithstanding that said cylinders of different diametersare employed, said last named means comprising coacting means on saidapparatus for enabling relative adjustment of the scanning unit and thecylinder to be scanned, to any one of different predetermined positionswith respect to the axis of rotation of said cylinder, corresponding tothe diameter of the particular cylinder to be scanned, and meansautomatically for causing said driving means to rotate the respectivecylinders in such manner that the peripheral speed, and hence the linearscanning speed, of the cylinders is substantially the same for saidcylinders of different diameters.

3. In apparatus for facsimile telegraphy, the combination of rotatableclutch means for releasably engaging and axially supporting in drivingrelation interchangeable message cylinders having substantiallydifferent diameters respectively for holding blanks of different sizesduring scanning operations, driving means operable at a predeterminedconstant speed for rotating said clutch means and causing rotation ofthe cylinder when engaged by the clutch means, a scanning unit havingmeans for scanning the blank on said cylinder, said scanning unit beingmounted on a carriage, means for progressively moving said carriagelongitudinally along said cylinder during rotation thereof to provideproper line feed of the scanning unit, and means for enabling thescanning means of the unit to be positioned properly with respect to theblanks notwithstanding that said vcylinders of different diameters areemployed, said last named means comprising a manually operablescrew-threaded rod and a screw-threaded member engageable thereby forenabling the scanning unit to be moved relative to the carriage to anyone of different predetermined positions, towards and from the axis ofrotation of said cylinder, corresponding to the diameter of theparticular cylinder to be scanned.

4. In apparatus for facsimile telegraphy, the combination of means forreleasably engaging and axially supportingv interchangeable messagecylinders having substantially different diameters respectively forholding blanks of different sizes during scanning operations, drivingmeans operable at a predetermined constant speed for rotating thecylinder at the time engaged by said supporting means, a scanning devicefor scanning the blank on said cylinder, a scanning carriage for thescanning device, means including a rotatable line'feed shaft for movingsaid carriage longitudinally along said cylinder during rotation thereofto provide proper line feed of the scanning device, and means forenabling the scanning device to be positioned properly with respect tothe blanks notwithstanding that said cylinders of different diametersare employed, said last named means comprising structure including aguideway on the scanning carriage for supporting and guiding the saidscanning device in a manner to enable the scanning device to be slidtowards and from the axis of rotation of said cylinder, coactingadjusting means on said carriage and scanning device for slid n thescanning device to any one of different operative positions, coactingmembers on said car-' riage and scanning device for indicating when thescanning device is set to a position corresponding to the diameter ofthe particular cylinder next to be scanned, one of said coactingindicating members having thereon a plurality of indicia respectivelycorresponding to said cylinders of different diameters, and avernierdevice operatively associated with said adjusting means forenabling a micrometer adjustment of the scanning device to be effectedafter the device has been set to one of the indicia corresponding to theparticular cylinder to be scanned.

5. \A facsimile transmitter and recorder unit comprising means forreleasably engaging and axially supporting in scanning positioninterchangeable transmitting and recording message cylinders havingsubstantially different diameters respectively for holding transmittingand recording blanks of different sizes during scanning operations,driving means operable at a predetermined speed for rotating thetransmitting and recording cylinders at the time engaged by saidsupporting means, transmitter and recorder scanning units having meansrespectively for scanning the blanks on said transmitting and recordingcylinders, said scanning units each being mounted on a carriage, meansfor progressively moving said carriages longitudinally along said

